The effect of alkyl length on the analytical signal of monoalkylethers of butylene oxide-ethylene oxide block copolymers in adsorptive stripping tensammetry

Monoalkylethers of butylene oxide-ethylene oxide block copolymers (ABE) bel ong to nonionic surfactants. ABE are electroinactive and do not contain chr omophoric groups. Therefore. the number of available analytical methods for ABE determination is very limited. Tensammetry provides an opportunity to increase the number of available analytical methods. A series of four surfa ctants corresponding to the formula: RO[CH2CH(C2H5)O](3)(CH,CH2O)(10) H whe re R = n-C10H11 (C10B3E10), n-C8H17 (C8B3E10), n-C6H13 (C6B3E10) Or n-C4H9 (C4B3E10), were investigated under the conditions of adsorptive stripping t ensammetry (AdST). The morphology of tensammetric peaks, as well as peak he ight dependences on the concentration of a corresponding surfactant. precon centration time and potential were investigated. All four surfactants form negative tensammetric peaks roughly between -1.6 and -1.7V. The peak height follows the sequence: C4B3E10 approximate to C6B3E10 much less than C10B3E 10<C8B3E10. Calibration plots show sigmoidal shapes in all instances, and p eak height dependences vs. preconcentration time show a <Gamma>-shap. The m aximum peak height is obtained at a preconcentration potential of -0.2 V Fo r C8B3E10 and C10B3E10, and at approximately -0.5 V for other cases. Anodic tensammetric curves show low values for analytical purposes.